Bicycle apparatus

ABSTRACT

A method of controlling an ABS unit is provided for controlling a braking force of a bicycle. The method includes determining whether a vehicle speed is greater than or equal to a prescribed speed, and then determining whether the bicycle is in a prescribed state. The prescribed state is at least one of a first state and a second state. The first state is a state in which a difference between a rotational speed of the front wheel and a rotational speed of the rear wheel is greater than or equal to a prescribed rotational speed. The second state is a state in which a change in the rotational speeds of the front and rear wheels is greater than or equal to a prescribed value. The method further includes controlling the ABS unit upon based on the vehicle speed and the prescribed state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 15/099,020, filed on Apr. 14, 2016. The entire disclosure of U.S.application Ser. No. 15/099,020 is hereby incorporated herein byreference. This application claims priority to Japanese PatentApplication No. 2015-091510, filed on Apr. 28, 2015. The entiredisclosure of Japanese Patent Application No. 2015-091510 is herebyincorporated herein by reference.

BACKGROUND Field of the Invention

The present invention generally relates to a bicycle apparatus. Morespecifically, the present invention relates to a bicycle apparatusequipped with an ABS unit (Antilock Brake System).

Background Information

A bicycle apparatus comprising an ABS unit is known. For example, abicycle apparatus having an ABS unit is disclosed in InternationalPublication No. WO 2014/108235. In the bicycle apparatus of thispublication, the ABS unit controls a braking force that is applied to awheel of a bicycle.

SUMMARY

Generally, the present disclosure is directed to various features of abicycle apparatus comprising an ABS unit.

The above-described bicycle apparatus is equipped with a drive sourcefor driving the ABS unit. For this reason, the bicycle apparatus isincreased in size as compared to a bicycle without an ABS unit.

One object of the present invention is to provide a bicycle apparatuswhich is not easily increased in size, even when equipped with an ABSunit.

In view of the state of the known technology and in accordance with anaspect of the present disclosure, a method of controlling an ABS unit isprovided for controlling a braking force of a bicycle. The methodincludes determining whether a vehicle speed is greater than or equal toa prescribed speed, and then determining whether the bicycle is in aprescribed state. The prescribed state is at least one of a first stateand a second state. The first state is a state in which a differencebetween a rotational speed of the front wheel and a rotational speed ofthe rear wheel is greater than or equal to a prescribed rotationalspeed. The second state is a state in which a change in the rotationalspeeds of the front and rear wheels is greater than or equal to aprescribed value. The method further includes controlling the ABS unitupon based on the vehicle speed and the prescribed state.

According to the bicycle apparatus described above, the size in noteasily increased even when mounting an ABS unit.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is a side elevational view of a bicycle that is equipped with abicycle apparatus that has an ABS unit in accordance with a firstembodiment.

FIG. 2 is a block diagram of the bicycle illustrated in FIG. 1.

FIG. 3 is a flowchart for a control executed by the control deviceillustrated in FIG. 1.

FIG. 4 is a flowchart for a control executed by the control deviceillustrated in FIG. 1.

FIG. 5 is a block diagram of a bicycle according to the secondembodiment.

FIG. 6 is a block diagram of a modified example of the bicycle.

DETAILED DESCRIPTION OF EMBODIMENTS

Selected embodiments will now be explained with reference to thedrawings. It will be apparent to those skilled in the bicycle field fromthis disclosure that the following descriptions of the embodiments areprovided for illustration only and not for the purpose of limiting theinvention as defined by the appended claims and their equivalents.

First Embodiment

Referring initially to FIG. 1, a bicycle 10 is illustrated that isequipped in accordance with a first embodiment. FIG. 1 is the outerappearance of an electrically assisted bicycle (hereinafter referred toas “bicycle 10”). The bicycle 10 comprises a frame 12, a front wheel 14,a rear wheel 16 and a handlebar 18. The frame 12 forms the main body ofthe bicycle 10. The front wheel 14 and the rear wheel 16 are wheelswhich are rotatably attached to the frame 12. The handlebar 18 isoperated for changing the orientation of the front wheel 14. The bicycle10 further comprises a pair of brake levers 20F and 20R which areoperating devices that are attached to the handlebar 18. The bicycle 10further comprises a brake device 22F (e.g., a front brake) for applyinga braking force to the front wheel 14, and a brake device 22R (e.g., arear brake) for applying a braking force to the rear wheel 16. Thediameter of the front wheel 14 and the rear wheel 16 are substantiallythe same.

Each of the brake devices 22F and 22R are, for example, a disc brake.The brake devices 22F and 22R are comprised of the disc rotors 26F and26R which are fixed to the hubs 24F and 24R so as to be integrallyrotated with the wheels, a pair of brake pads (not shown), and thecalipers 28F and 28R which brake the rotation of the disk rotors 26F and26R, by pressing the brake pads to the disk rotors 26F and 26R.

The brake lever 20F among the pair of brake levers 20F and 20R isconnected to the caliper 28F for braking the front wheel 14. The brakelever 20R is connected to the caliper 28R for braking the rear wheel 16.The calipers 28F and 28R squeeze the disk rotors 26F and 26F via thebrake pads, by the corresponding brake levers 20F and 20R beingoperated. The rotation of the wheels is thereby slowed or stopped butactuation of the calipers 28F and 28R.

Each of the brake levers 20F and 20R comprises a base portion 21A, alever portion 21B and a piston (not shown). The base portion 21A isattached to the handlebar 18. The lever portion 21B is rotatably coupledwith the base portion 21A. The piston (not shown) is coupled to thelever portion 21B. When the brake levers 20F and 20R are operated, thelever portions 21B are displaced with respect to the base portions 21A,from their initial positions, which are the positions of the leverportions 21B when a force is not applied to them.

The bicycle 10 further comprises a drive mechanism 30 for transmitting adrive force to the rear wheel. The drive mechanism 30 comprises a driveunit 32 which is detachably fixed to the frame 12. The drive mechanism30 further comprises a crankshaft 34 which is rotatably attached to thedrive unit 32. The drive unit 32 comprises an assist motor 36 and ahousing 38. The assist motor 36 is configured to add an assisting forceto a manual drive force, which is inputted from the crankshaft 34. Thehousing 38 is configured to house a plurality of mechanical elements.The assist motor 36 is an electric motor, and is provided to the housing38. The assist motor 36 can be provided to the internal space of thehousing 38. The bicycle 10 further comprises a battery 40 for supplyingelectric power to the assist motor 36. The battery 40 is attached to theframe 12.

The drive mechanism 30 further comprises a pair of crank arms 42 and apair of pedals 44. The crank arms 42 are coupled to the crankshaft 34.One of the pedals 44 is rotatably attached to one of the crank arms 42.The drive mechanism 30 further comprises a front sprocket 48, a rearsprocket 50 and a chain 52. The front sprocket 48 is coupled to thecrankshaft 34 via a one-way clutch 46 (refer to FIG. 2). The rearsprocket 50 is rotatably attached to the hub 24R of the rear wheel 16via a free wheel (not shown). The chain 52 is wound onto the frontsprocket 48 and the rear sprocket 50.

If a manual drive force is inputted to the pedal 44 for rotating thecrank arm 42 in a forward driving direction, then the crank arm 42 andthe crankshaft 34 are integrally rotated forward with respect to theframe 12. The rotation of the crankshaft 34 rotates the front sprocket48, and the rotation of the front sprocket 48 is then transmitted to therear sprocket 50 and the rear wheel 16 by the chain 52. On the otherhand, if a manual drive force is inputted to the pedal 44 for rotatingthe crank arm 42 in a backward non-driving direction, and then the crankarm 42 and the crankshaft 34 are integrally rotated backward withrespect to the frame 12. The rotation of the crankshaft 34 is nottransmitted to the front sprocket 48 by the one-way clutch 46.

The assist motor 36 is rotated in a first direction in accordance withthe manual drive force which rotates the crank arm 42 forward. When theassist motor 36 is rotated in the first direction, the rotation of theassist motor 36 is transmitted to the front sprocket 48 via a speedreducing mechanism (not shown) and a one-way clutch 54 (refer to FIG.2). Accordingly, an assisting force is added to the manual drive force.

FIG. 2 shows the electrical or the mechanical connection relationshipsof the bicycle 10 (refer to FIG. 1). The broken lines of FIG. 2 show theelectrical connection relationships of the bicycle 10. The solid linesof FIG. 2 show the mechanical connection relationships of the bicycle10.

The bicycle 10 further comprises a bicycle apparatus 56 which is formedof a plurality of mechanical elements including the drive unit 32 (referto FIG. 1). The bicycle apparatus 56 comprises an ABS unit 58F and acontrol device 60. The ABS unit 58F is driven by the assist motor 36 forcontrolling a braking force which is applied from the caliper 28F to thefront wheel 14 (refer to FIG. 1). The control device 60 is programmedfor controlling the assist motor 36 and the ABS unit 58F. The ABS unit58F is housed in the internal space of the housing 38.

The ABS unit 58F comprises a pump 62 and a reservoir 64F. The pump 62supplies the hydraulic oil and applies a hydraulic pressure to thecaliper 28F. The reservoir 64F accumulates the hydraulic oil. The pump62 includes, for example, a piston pump, a gear pump, or the like. Aone-way clutch 66 is disposed between the assist motor 36 and the pump62. The one-way clutch 66 is a compositional element of the bicycleapparatus 56. The pump 62 is mechanically connected to the assist motor36 via the one-way clutch 66.

The one-way clutch 66 transmits the rotation of the assist motor 36 tothe pump 62, when an output shaft of the assist motor 36 is rotated in asecond direction, which is the opposite of the first direction.Accordingly, when the assist motor 36 is rotated in the seconddirection, the pump 62 is driven via the one-way clutch 66. On the otherhand, the one-way clutch 66 does not transmit the rotation of the assistmotor 36 to the pump 62, when the output shaft of the assist motor 36 isrotated in the first direction. The bicycle apparatus 56 can furthercomprise a speed reducing mechanism (not shown) on a power transmissionpath between the assist motor 36 and the pump 62.

The ABS unit 58F further comprises a first valve 68F and a second valve70F which adjust the hydraulic pressure which is applied to the caliper28F. The first valve 68F is disposed on a pipeline which connects thebrake lever 20F and the caliper 28F. The second valve 70F is disposed ona pipeline which connects the caliper 28F and the reservoir 64F.

The first valve 68F and the second valve 70F include a solenoid valve ora motorized valve. When each of the valves 68F and 70F includes asolenoid valve, preferably from the point of view of suppressing thewaste of the power, the solenoid valve of the first valve 68F is openedwhen power not provided and the solenoid valve of the second valve 70Fis closed when power not provided. The hydraulic pressure that isapplied to the caliper 28F is controlled by the control device 60 forcontrolling the opening and closing of each of the valves 68F and 70F.

When the hydraulic pressure that is applied to the caliper 28F is high,the caliper 28F is brought close to the disk rotor 26F (refer to FIG.1). In this case, the caliper 28F squeezes the disk rotor 26F via thebrake pad, and the rotation of the front wheel 14 is braked. On theother hand, when the hydraulic pressure that is applied to the caliper28F is low, the caliper 28F is separated from the disk rotor 26F.Accordingly, the rotation of the front wheel 14 is not braked.

The hydraulic oil that is supplied from the pump 62 flows through thefirst pipeline 72F, the second pipeline 74F, and the third pipeline 76F.The first pipeline 72F, the second pipeline 74F, and the third pipeline76F are each a pipeline that branches into three. The three ends of thefirst pipeline 72F are connected to the brake lever 20F, the pump 62,and the first valve 68F. The three ends of the second pipeline 74F areconnected to the caliper 28F, the first valve 68F, and the second valve70F. The three ends of the third pipeline 76F are connected to the pump62, the reservoir 64F, and the second valve 70F.

The ABS unit 58F further comprises a first check valve 78F and a secondcheck valve 80F. The first check valve 78F is disposed in the firstpipeline 72F. The second check valve 80F is disposed in the thirdpipeline 76F. The first check valve 78F enables the hydraulic oil toflow from the pump 62 to the brake lever 20F, and does not allow thehydraulic oil to flow to in the opposite direction. The second checkvalve 80F enables the hydraulic oil to flow from the reservoir 64F tothe pump 62, and does not allow the hydraulic oil to flow in theopposite direction. Accordingly, the hydraulic oil is supplied from thethird pipeline 76F, which is connected to the reservoir 64F, to thefirst pipeline 72F, by the pump 62 being driven. When the pump 62 isdriven, the hydraulic pressure of the first pipeline 72F is raised.Further, if the second valve 70F is opened, then the hydraulic oil flowsfrom the second pipeline 74F to the third pipeline 76F via the secondvalve 70F, along with the pump 62 being driven.

The bicycle 10 further comprises a first detection device 82F (e.g., abrake lever detection device), a second detection device 84F (e.g., afront wheel detection device) and a second detection device 84R (e.g., arear wheel detection device). The first detection device 82F isconfigured to detect the operating state of the brake lever 20F. Thesecond detection device 84F is configured to detect the rotation stateof the front wheel 14. The second detection device 84R is configured todetect the rotation state of the rear wheel 16 (refer to FIG. 1). Thefirst detection device 82F and each of the second detection devices 84Fand 84R are electrically connected to the control device 60.

The first detection device 82F is a first sensor for detecting whetheror not a user is operating the lever portion 21B of the brake lever 20F(refer to FIG. 1). The first detection device 82F is, for example anangle sensor which is attached to the brake lever 20F. The angle sensorincludes, for example, a potentiometer, a magnetic sensor, an opticalsensor, or the like. The first detection device 82F is configured todetect the operating state of the brake lever 20F by detecting theoperation angle, which is the angle of the lever portion 21B withrespect to the base portion 21A (refer to FIG. 1). Meanwhile, in thecase that the angle sensor includes a magnetic sensor, a magnetic sensorprovided to the base portion 21A detects the movement of a magnetprovided to the lever portion 21B.

The second detection device 84F comprises a magnetic sensor and amagnet. The magnetic sensor of the second detection device 84F isattached to, for example, the frame 12 (refer to FIG. 1) in the vicinityof the front wheel 14. The magnet of the second detection device 84F isattached to the disk rotor 26F or the spoke of the front wheel 14. Thesecond detection device 84F detects the rotational speed of the frontwheel 14 in the rotation state, by the magnetic sensor detecting themagnet. The second detection device 84F can be provided with severalmagnets, which are arranged to rotate along with the front wheel 14.These magnets can be provided in the circumferential direction of thefront wheel 14, and can be formed in an annular shape and magnetized inalternately different polarities in the circumferential direction.

The second detection device 84R comprises a magnetic sensor and amagnet. The magnetic sensor of the second detection device 84R isattached to, for example, the frame 12 in the vicinity of the rear wheel16. The magnet of the second detection device 84R is attached to thedisk rotor 26R or the spoke of the rear wheel 16. The second detectiondevice 84R detects the rotational speed of the rear wheel 16 in therotation state, by the magnetic sensor detecting the magnet. The seconddetection device 84R can be provided with several magnets, whicharranged to rotate along with the rear wheel 16. These magnets can beprovided in the circumferential direction of the rear wheel 16, and canbe formed in an annular shape and magnetized with alternately differentpolarities in the circumferential direction.

The control device 60 calculates the vehicle speed, which is the speedof the bicycle 10, on the basis of the detection result of at least onerotational speed of the front wheel 14 and the rear wheel 16, which isdetected by each of the second detection devices 84F and 84R. Thecontrol device 60 calculates the vehicle speed of the bicycle 10, on thebasis of the detection result of the higher rotational speed, of thedetection results of the second detection devices 84F and 84R.

The bicycle 10 further comprises an operating unit 86 and a torquesensor 87. The operating unit 86 is attached to the handlebar 18 (referto FIG. 1), and is operated for switching the operation mode of theassist motor 36. The torque sensor 87 is configured to detect the manualdrive force. The operating unit 86 and the torque sensor 87 areelectrically connected to the control device 60. The torque sensor 87 isprovided on a power transmission path between, for example, thecrankshaft 34 and the front sprocket 48. The torque sensor 87 includes,for example, a strain sensor or a magnetostrictive sensor.

The operating unit 86 comprises an assist selection switch (not shown)for selecting the operation mode of the assist motor 36. When theoperation mode of the assist motor 36 is set to an assist ON mode by theassist selection switch, power is supplied from the battery 40 (refer toFIG. 1) to the assist motor 36 in accordance with the detection resultof the torque sensor 87. On the other hand, when the operation mode ofthe assist motor 36 is set to an assist OFF mode by the assist selectionswitch, the manual drive force is not assisted by the assist motor 36.

The operating unit 86 further comprises an ABS operation changeoverswitch (not shown) for switching between an ABS operating mode whichputs the ABS unit 58F in an operable state, and an ABS non-operatingmode which puts the ABS unit 58F in a non-operating state. The controlof the ABS unit 58F by the control device 60 is carried out by the ABSnon-operating mode being switched to the ABS operating mode by the ABSoperation changeover switch. The control of the ABS unit 58F by thecontrol device 60 is not dependent on an operation of the assistselection switch.

The control device 60 controls the output and the rotational directionof the assist motor 36, on the basis of the detection results of thefirst detection device 82F and the second detection devices 84F and 84R.The control device 60 comprises a microprocessor and a memory. Thecontrol device 60 is operated by the microprocessor executing a programwhich is stored in the memory. The control device 60 switches theopen/close state of the first valve 68F and the second valve 70F betweena first pattern, a second pattern, and a third pattern, on the basis ofthe detection results of the first detection device 82F and the seconddetection devices 84F and 84R. Table 1 shows the open/close state of thefirst valve 68F and the second valve 70F in each of the patterns.

TABLE 1 opened/closed state first valve second valve first patternopened closed second pattern closed opened third pattern closed closed

The first pattern is a state in which the first valve 68F is opened andthe second valve 70F is closed. The second pattern is a state in whichthe first valve 68F is closed and the second valve 70F is opened. Thethird pattern is a state in which both the first valve 68F and thesecond valve 70F are closed. When set to the ABS non-operating mode bythe operating unit 86, the first pattern is selected.

When the first pattern is selected, a piston of the brake lever 20Fcompresses the hydraulic oil in the first pipeline 72F and the secondpipeline 74F, by the brake lever 20F being operated. That is, thehydraulic pressure of the second pipeline 74F is raised, and thehydraulic pressure which is applied to the caliper 28F is increased.Accordingly, the caliper 28F squeezes the disk rotor 26F via the brakepad, and the rotation of the front wheel 14 is braked, by the brakelever 20F being operated.

When the second pattern is selected, the hydraulic oil in the secondpipeline 74F is moved into the third pipeline 76F; therefore, thehydraulic pressure of the second pipeline 74F is reduced. Accordingly,the hydraulic pressure which is applied to the caliper 28F is alsoreduced, and the braking force which is applied to the front wheel 14 isweakened. The hydraulic oil of the third pipeline 76F flows into thereservoir 64F and the pump 62. In the second pattern, since the firstvalve 68F is closed, the hydraulic pressure of the second pipeline 74Fdoes not change even if the brake lever 20F is operated. Accordingly,the braking force which is applied to the front wheel 14 is notdependent on the operation of the brake lever 20F.

When the third pattern is selected, the hydraulic oil in the secondpipeline 74F is held in the second pipeline 74F; therefore, thehydraulic pressure of the second pipeline 74F is maintained.Accordingly, the hydraulic pressure which is applied to the caliper 28Fis also maintained, and the braking force which is applied to the frontwheel 14 is kept constant. In the third pattern, since the first valve68F is closed, the braking force which is applied to the front wheel 14is not dependent on the operation of the brake lever 20F, in the sameway as in the second pattern.

FIGS. 3 and 4 are flowcharts of the ABS operation control which isexecuted by the control device 60. The control device 60 starts thesteps shown in FIGS. 3 and 4, by being set to the ABS operating mode bythe operating unit 86. Thus, when set to the ABS operating mode, thesteps shown in FIGS. 3 and 4 are started by turning ON the power of thecontrol device 60. The ON and OFF of the power of the control device 60is switched by the operating unit 86. Here, a case in which the assistON mode is selected by the operating unit 86 will be described.

The control device 60 causes the assist motor 36 to be rotated in thefirst direction in accordance with the manual drive force. Further, theopen/close state of the valves 68F and 70F is maintained in the firstpattern until switched by the control device 60.

The control device 60 determines whether or not the brake lever 20F isbeing operated on the basis of the detection result of the firstdetection device 82F, in step S1. If the brake lever 20F is determinedto be not operated in step S1, the steps of step S1 are executed again.On the other hand, if the brake lever 20F is determined to be operatedin step S1, the steps of step S2 are executed. When executing an ABSoperation control only to the front wheel 14 as in the present firstembodiment, only the brake lever 20F which corresponds to the frontwheel 14 is set as the detection target. On the other hand, whenexecuting an ABS operation control only to the rear wheel 16, only thebrake lever 20R which corresponds to the rear wheel 16 is set as thedetection target.

The control device 60 reduces the output of the assist motor 36 whencausing the assist motor 36 to be rotated in the first direction inaccordance with the manual drive force, in step S2. Then, the controldevice 60 ultimately stops the assist motor 36 by causing the output ofthe assist motor 36 to be reduced.

The control device 60 determines whether or not the vehicle speed of thebicycle 10 is greater than or equal to a prescribed speed, on the basisof the detection results of the second detection devices 84F and 84R, instep S3. The prescribed speed is preferably a speed of, for example,less than or equal to 5 km/hour. If the vehicle speed is determined tobe greater than or equal to the prescribed speed in step S3, the stepsof step S4 are executed.

The control device 60 determines whether or not the state of the bicycle10 is in a prescribed state, on the basis of the detection results ofthe second detection devices 84F and 84R, in step S4. The prescribedstate is a state in which at least one of the following is established:a state in which the difference between the rotational speed of thefront wheel 14 and the rotational speed of the rear wheel 16 is greaterthan or equal to a prescribed speed, and, a state in which a change inthe rotational speed that is greater than or equal to a prescribed valuehas occurred in the wheels.

When executing an ABS operation control only to the front wheel 14, asin the present first embodiment, only the front wheel 14 is set as thedetection target, in terms of whether or not the state is one in which achange in the rotational speed that is greater than or equal to theprescribed value has occurred in the wheels. On the other hand, whenexecuting an ABS operation control only to the rear wheel 16, only therear wheel 16 is set as the detection target, in terms of whether or notthe state is one in which a change in the rotational speed that isgreater than or equal to the prescribed value has occurred in thewheels. The prescribed state being established suggests the possibilitythat the front wheel 14, which is braked by an operation of the brakelever 20F, will be locked.

If the state of the bicycle 10 is determined to be in the prescribedstate in step S4, the steps of the step S6 is executed. On the otherhand, if the vehicle speed is determined to be less than the prescribedspeed in the step S3, or, if the state of the bicycle 10 is determinedto be not in the prescribed state in the step S4, the steps of the stepS5 is executed.

The control device 60 returns the output of the assist motor 36 so thata drive force corresponding to the manual drive force will be outputtedfrom the assist motor 36, in step S5. That is, the control device 60returns the output of the assist motor 36, which was caused to beforcibly reduced in the step S2, to a state in which a drive forcecorresponding to the manual drive force is outputted. Then, afterfinishing the steps of step S5, the control device 60 executes the stepsof the step S1 again.

The control device 60 switches the open/close state of the first valve68F and the second valve 70F from the first pattern to the secondpattern, in the step S6. Accordingly, the first valve 68F is closed andthe second valve 70F is opened. Accordingly, the hydraulic pressurewhich is applied to the caliper 28F is reduced, and the braking forcewhich is applied to the front wheel 14 is weakened.

The control device 60 causes the assist motor 36 to be rotated in thesecond direction, in the step S7. Drive force is transmitted from theassist motor 36 to the pump 62 and the pump 62 is driven by the assistmotor 36 being rotated in the second direction. Accordingly, thehydraulic oil is supplied to the first pipeline 72F and the hydraulicpressure of the first pipeline 72F starts to be raised. With thehydraulic pressure of the first pipeline 72F being raised, the leverportion 21B of the brake lever 20F is pushed back toward the initialposition.

The control device 60 determines whether or not a prescribed time haselapsed since executing the steps of the step S6, in the step S8. If theprescribed time is determined to have not elapsed in step S8, the stepsof step S8 is executed again. On the other hand, if the prescribed timeis determined to have elapsed in the step S8, the steps of the step S9is executed.

The control device 60 switches the open/close state of the first valve68F and the second valve 70F from the second pattern to the thirdpattern, in the step S9. Accordingly, both the first valve 68F and thesecond valve 70F are closed. Accordingly, the hydraulic pressure whichis applied to the caliper 28F is maintained, and the braking force whichis applied to the front wheel 14 is kept constant. The hydraulicpressure which is applied to the caliper 28F is continuously lowereduntil the valves 68F and 70F are switched from the second pattern to thethird pattern.

The control device 60 determines whether or not the brake lever 20F isbeing operated on the basis of the detection result of the firstdetection device 82F, in the step S10. If the brake lever 20F isdetermined to be operated in step S10, the steps of the step S11 isexecuted.

The control device 60 determines whether or not the vehicle speed of thebicycle 10 is greater than or equal to a prescribed speed, on the basisof the detection results of the second detection devices 84F and 84R, inthe step S11. The prescribed speed is preferably a speed of, forexample, less than or equal to 5 km/hour. If the vehicle speed isdetermined to be greater than or equal to the prescribed speed in thestep S11, the steps of the step S13 are executed. On the other hand, ifthe brake lever 20F is determined to be not operated in step S10, or, ifthe vehicle speed is determined to be less than the prescribed speed instep S11, the steps of the step S12 is executed.

The control device 60 switches the open/close state of the first valve68F and the second valve 70F from the third pattern to the firstpattern, in the step S12. Accordingly, the first valve 68F is opened andthe second valve 70F is closed. Accordingly, the rotation of the frontwheel 14 will be braked in conjunction with an operation of the brakelever 20F. Then, after finishing the steps of the step S12, the controldevice 60 executes the steps of the step S19 again.

In the step S13, the control device 60 executes substantially the samestep as the step that is executed in the step S4. If the state of thebicycle 10 is determined to be in the prescribed state in the step S13,the step S14 is executed.

In step S14, the control device 60 executes substantially the same stepas the step that is executed in step S6. Then, after finishing the stepS14, the control device 60 executes the step S8 again. When executingthe step S8 after the step S14, the control device 60 determines whetheror not a prescribed time has elapsed since executing the step S14.

On the other hand, if the state of the bicycle 10 is determined to benot in the prescribed state in step S13, the step S15 is executed. Instep S15, the control device 60 executes substantially the same step asthe step that is executed in step S12.

The control device 60 determines whether or not the brake lever 20F isbeing operated on the basis of the detection result of the firstdetection device 82F, in step S16. If the brake lever 20F is determinedto be operated in step S16, the step S17 is executed.

The control device 60 determines whether or not the vehicle speed of thebicycle 10 is greater than or equal to a prescribed speed, on the basisof the detection results of the second detection devices 84F and 84R, instep S17. The prescribed speed is preferably a speed of, for example,less than or equal to 5 km/hour. If the vehicle speed is determined tobe greater than or equal to the prescribed speed in step S17, the stepS18 is executed. On the other hand, if the brake lever 20F is determinedto be not operated in step S16, or, if the vehicle speed is determinedto be less than the prescribed speed in step S17, the step S19 isexecuted.

In step S18, the control device 60 executes substantially the same stepas the step that is executed in step S4. If the state of the bicycle 10is determined to be in the prescribed state in step S18, the step S14 isexecuted. On the other hand, if the state of the bicycle 10 isdetermined to be not in the prescribed state in step S18, the step S19is executed.

The control device 60 determines whether or not a prescribed time haselapsed since executing the step S6 or the step S14, in the step S19.Specifically, whether or not a prescribed time has elapsed since thelast step in which the open/close state of the valves 68F and 70F wasswitched to the second pattern is determined. The prescribed time isdetermined in advance, for example, on the basis of the time necessaryto raise the amount of the hydraulic oil in the first pipeline 72F andthe second pipeline 74F to a prescribed amount. The prescribed amountis, for example, substantially the same amount as the state prior to thestep S6.

If the prescribed time is determined to have not elapsed in step S19,the step S19 is executed again. On the other hand, if the prescribedtime is determined to have elapsed in step S19, the step S20 isexecuted.

The control device 60 stops the rotation of the assist motor 36 in thesecond direction, in step S20. Accordingly, the driving of the pump 62is stopped. The control device 60 repeatedly executes the steps of thesteps S1 to S20 until the ABS operating mode is switched to the ABSnon-operating mode by the operating unit 86. If the assist OFF mode isselected by the operating unit 86, an ABS operation control in which thesteps of the step S2 and the step S5 are omitted from the step shown inFIG. 3 and FIG. 4 is executed.

The action of the bicycle apparatus 56 will be described with referenceto FIGS. 1 and 2.

The user operates the operating unit 86 before boarding, or whileriding, the bicycle 10. The assist motor 36 is rotated in the firstdirection in accordance with the manual drive force that is inputted tothe pedal 44, and an assisting force is added to the manual drive force,with the mode being set to the assist ON mode by the operating unit 86.

If the user operates the brake lever 20F when the vehicle speed isgreater than or equal to a prescribed speed, then there are cases inwhich the front wheel 14 will be locked, depending on the state of theroad surface or the strength with which the user grips the brake lever20F. At this time, the assist motor 36 and the ABS unit 58F arecontrolled by the control device 60, and the braking force which isapplied to the front wheel 14 of the bicycle 10 is controlled.Specifically, the steps S1 to S20 shown in FIGS. 3 and 4 are repeatedlyexecuted, with the mode being set to the ABS operating mode by theoperating unit 86.

Accordingly, even if the front wheel 14 is about to be locked followingan operation of the brake lever 20F, the ABS unit 58F is driven by thecontrol device 60 and the front wheel 14 is restored to the normalstate. Accordingly, the user is less likely to lose balance duringtraveling.

Further, the pump 62 of the ABS unit 58F is driven by the assist motor36 being rotated in the second direction. That is, assisting force isadded to the manual drive force by the assist motor 36 being rotated inthe first direction, and the pump 62 is driven by the assist motor 36being rotated in the second direction. Accordingly, compared to aconfiguration in which assisting force is added to the manual driveforce by the assist motor 36 and the pump 62 is driven by a drive sourcewhich is different from the assist motor 36, the bicycle apparatus 56 isless likely to be increased in size. Accordingly, the embodiment cancontribute to the reduction in size and weight of the bicycle 10.

According to the bicycle apparatus 56 of the first embodiment, thefollowing effects are further achieved.

(1) The bicycle apparatus 56 causes the control device 60 to reduce theoutput of the assist motor 36, if the brake lever 20F is operated whenthe assist motor 36 is being rotated in the first direction.Accordingly, when the front wheel 14 is about to be locked following anoperation of the brake lever 20F, the user is less likely to losebalance during traveling, since the output of the assist motor 36 issmall.

(2) In the bicycle apparatus 56, the hydraulic pressure which is appliedto the caliper 28F is reduced, and the pump 62 is driven by the assistmotor 36 being rotated in the second direction, by the assist motor 36and the ABS unit 58F being controlled by the control device 60.Accordingly, compared to a configuration in which the pump 62 is drivenafter reducing the hydraulic pressure that is applied to the caliper28F, the amount of the hydraulic oil which flows in the first pipeline72F and the second pipeline 74F can be raised at an early stage to aprescribed amount more easily.

(3) In the case that the rotational speed of the wheels of the bicycle10 is less than a prescribed speed, that is, in the case that thevehicle speed of the bicycle 10 is less than a prescribed speed, theuser is less likely to lose balance while traveling, even if the wheelsare locked. In light of this point, the bicycle apparatus 56 does notdrive the ABS unit 58F, or stops the driving of the ABS unit 58F, whenthe vehicle speed is determined to be in a state of less than aprescribed speed by the control device 60. Accordingly, the waste ofpower can be suppressed compared to a configuration in which the ABSunit 58F is driven, or a configuration in which the ABS unit 58F iscontinued to be driven, even when the vehicle speed is less than aprescribed speed.

(4) In the bicycle apparatus 56, the assist motor 36 and the ABS unit58F are housed in the internal space of the housing 38. Accordingly,compared to a configuration in which a part of or all of the ABS unit58F is provided outside the housing 38, the embodiment can contribute tothe protection of the ABS unit 58F.

(5) According to the bicycle 10, there are cases in which the frontwheel 14 will be about to be locked again when the brake lever 20F isbeing operated, even after the front wheel 14 is restored to the normalstate by the hydraulic pressure which is applied to the caliper 28Fbeing reduced following an operation of the ABS unit 58F. In light ofthis point, in the bicycle apparatus 56, the control device 60 executesthe steps of step S16-step S18 after the front wheel 14 is restored tothe normal state by the hydraulic pressure which is applied to thecaliper 28F being reduced. Accordingly, the user is less likely to losebalance even when the wheel is about to be locked again, since the ABSunit 58F will be operated again.

Second Embodiment

The bicycle apparatus 56 according to the second embodiment differs fromthe bicycle apparatus 56 according to the first embodiment in the pointsdescribed below, and comprises configurations that are substantially thesame as the bicycle apparatus 56 according to the first embodiment inthe other points. In the description of the bicycle apparatus 56according to the second embodiment, the same reference symbols are givento configurations that are shared with the bicycle apparatus 56according to the first embodiment, and some or all of the descriptionsof the configurations thereof are omitted.

FIG. 5 shows the electrical or the mechanical connection relationshipsof the bicycle 10 (refer to FIG. 1). The broken lines of FIG. 5 show theelectrical connection relationships of the bicycle 10. The solid linesof FIG. 5 show the mechanical connection relationships of the bicycle10.

The bicycle apparatus 56 comprises an ABS unit, which is driven by theassist motor 36, for controlling the braking force which is applied fromthe calipers 28F and 28R to the wheels. The ABS unit includes a firstABS unit 58F and a second ABS unit. The first ABS unit 58F is configuredto control the braking force which is applied to the front wheel 14(refer to FIG. 1). The second ABS unit 58R is configured to control thebraking force which is applied to the rear wheel 16 (refer to FIG. 1).The ABS units 58F and 58R are housed in the internal space of thehousing 38. The control device 60 controls the assist motor 36, thefirst ABS unit 58F and the second ABS unit 58R. Since the configurationof the first ABS unit 58F is substantially the same as the ABS unit 58Fof the first embodiment, a part or all of the description thereof willbe omitted.

The second ABS unit 58R comprises a pump 62 which is shared with thefirst ABS unit 58F, and a reservoir 64R which accumulates the hydraulicoil. The pump 62 is a common compositional element among the ABS units58F and 58R, and plays the role of providing hydraulic pressure to thecalipers 28F and 28R. The pump 62 can be provided to each of the ABSunits 58F and 58R.

The second ABS unit 58R further comprises a first valve 68R and a secondvalve 70R for adjusting the hydraulic pressure which is applied to thecaliper 28R. The first valve 68R has substantially the sameconfiguration as the first valve 68F in the first ABS unit 58F. Thefirst valve 68R is disposed on a pipeline which connects the brake lever20R and the caliper 28R. The second valve 70R has substantially the sameconfiguration as the second valve 70F in the first ABS unit 58F. Thesecond valve 70R is disposed on a pipeline which connects the caliper28R and the reservoir 64R.

When the hydraulic pressure that is applied to the caliper 28R is high,the caliper 28R is brought close to the disk rotor 26R (refer to FIG.1). In this case, the caliper 28R squeezes the disk rotor 26R via thebrake pad, and the rotation of the rear wheel 16 is braked. On the otherhand, when the hydraulic pressure that is applied to the caliper 28R islow, the caliper 28R is separated from the disk rotor 26R. Accordingly,the rotation of the rear wheel 16 is not braked.

The hydraulic oil that is supplied from the pump 62 flows through thefirst pipeline 72F, the second pipeline 74F, and the third pipeline 76Fin the first ABS unit 58F, as well as flowing through the first pipeline72R, the second pipeline 74R, and the third pipeline 76R in the secondABS unit 58R. The first pipeline 72R, the second pipeline 74R, and thethird pipeline 76R are each a pipeline that branches into three.

Each end of the first pipeline 72R is connected to the brake lever 20R,the pump 62, and the first valve 68R. The first pipeline 72R isconnected to the pump 62 by being connected to a portion between thepump 62 and the first check valve 78F of the first pipeline 72F. Eachend of the second pipeline 74R is connected to the caliper 28R, thefirst valve 68R, and the second valve 70R. Each end of the thirdpipeline 76R is connected to the pump 62, the reservoir 64R, and thesecond valve 70R. The third pipeline 76R is connected to the pump 62 bybeing connected to a portion between the pump 62 and the second checkvalve 80F of the third pipeline 76F.

The second ABS unit 58R further comprises a first check valve 78R and asecond check valve 80R. The first check valve 78R is disposed on thefirst pipeline 72R. The second check valve 80R which is disposed on thethird pipeline 76R. The first check valve 78R has substantially the sameconfiguration as the first check valve 78F in the first ABS unit 58F.The second check valve 80R has substantially the same configuration asthe second check valve 80F in the first ABS unit 58F.

The bicycle 10 further comprises a first detection device 82R (e.g., abrake lever detection device) for detecting the operating state of thebrake lever 20R. The first detection device 82R has substantially thesame configuration as the first detection device 82F. The firstdetection device 82R is electrically connected to the control device 60.

The operating unit 86 further comprises an ABS operation changeoverswitch (not shown) for switching between an ABS operating mode whichputs the ABS units 58F and 58R in an operable state, and an ABSnon-operating mode which puts the ABS unit 58F and 58R in anon-operating state.

The control device 60 controls the output and the rotational directionof the assist motor 36, on the basis of the detection results of thefirst detection devices 82F and 82R and the second detection devices 84Fand 84R. The control device 60 switches the open/close state of thefirst valve 68F and the second valve 70F in the first ABS unit 58F, andthe open/close state of the first valve 68R and the second valve 70R inthe second ABS unit 58R, on the basis of the detection results of thefirst detection devices 82F and 82R and the second detection devices 84Fand 84R. The control regarding the switching of the open/close state ofthe valves 68R and 70R in the second ABS unit 58R is substantially thesame as the control regarding the switching of the open/close state ofthe valves 68F and 70F in the first ABS unit 58F.

The control device 60 starts the step shown in FIGS. 3 and 4, by beingset to the ABS operating mode by the operating unit 86. The controldevice 60 determines whether or not the brake levers 20F and 20R arebeing operated on the basis of the first detection devices 82F and 82R,in the step S1, the step S10 and the step S16. When at least one of thebrake levers 20F and 20R is being operated, the brake levers 20F and 20Rare determined to be operated.

The control device 60 switches the open/close state of at least one ofthe first valve 68F and the second valve 70F in the first ABS unit 58F,and the first valve 68R and the second valve 70R in the second ABS unit58R, from the first pattern to the second pattern, in the step S6.

For example, the control device 60 operates the ABS unit 58F and 58Rthat corresponds to the wheel in which a change in the rotational speedof a prescribed value or greater is detected in the step S4. That is,when the state is determined to be one in which a change in therotational speed which is greater than or equal to a prescribed valuehas occurred in the rear wheel 16 in step S4, the control device 60switches the open/close state of the first valve 68R and the secondvalve 70R in the second ABS unit 58R, from the first pattern to thesecond pattern, in step S6.

Further, the control device 60 operates the ABS unit 58F and 58R thatcorresponds to the wheel with the lower rotational speed, when, forexample, the difference between the rotational speed of the front wheel14 and the rotational speed of the rear wheel 16 is detected to havebecome greater than or equal to a prescribed speed, in step S4. That is,when the rotational speed of the rear wheel 16 is determined to be lowerthan the rotational speed of the front wheel 14 by a prescribed speed ormore in the step S4, the control device 60 switches the open/close stateof the first valve 68R and the second valve 70R in the second ABS unit58R, from the first pattern to the second pattern, in the step S6. Thesame applies to the step S14 as the step S6.

The action of the bicycle apparatus 56 will be described with referenceto FIGS. 1 and 5. If the user operates the brake levers 20F and 20R whenthe vehicle speed is greater than or equal to a prescribed speed, thereare cases in which at least one of the front wheel 14 and the rear wheel16 will be locked, depending on the state of the road surface or thestrength with which the user grips the brake levers 20F and 20R. At thistime, the assist motor 36 and the ABS units 58F and 58R are controlledby the control device 60, and the braking force which is applied to thefront wheel of the bicycle 10 is controlled.

Accordingly, even if at least one of the front wheel 14 and the rearwheel 16 is about to be locked following an operation of the brakelevers 20F and 20R, the ABS units 58F and 58R are driven by the controldevice 60 and the wheels are restored to the normal state. Accordingly,the user is less likely to lose balance during traveling.

According to the bicycle apparatus 56 of the second embodiment, thefollowing effects are obtained in addition to the effects of (1) to (5)obtained according to the first embodiment.

(6) The bicycle apparatus 56 comprises the first ABS unit 58F forcontrolling the braking force which is applied to the front wheel 14,and the second ABS unit 58R for controlling the braking force which isapplied to the rear wheel 16. Accordingly, even if one or both of thefront wheel 14 and the rear wheel 16 are about to be locked following anoperation of the brake levers 20F and 20R, the front wheel 14 and therear wheel 16 are restored to the normal state, by the ABS units 58F and58R being operated. Accordingly, the user is less likely to lose balanceduring traveling, compared to a configuration in which only one of thefirst ABS unit 58F or the second ABS unit 58R is provided.

Modified Examples

The descriptions relating to each embodiment are examples of forms thatthe bicycle apparatus according to the present invention can take, andare not intended to limit the forms thereof. The bicycle apparatusaccording to the present invention can, in addition to the embodiments,take the forms of the modified examples of the embodiments shown below,as well as forms that combine at least two modified examples that arenot mutually exclusive.

-   -   The control device 60 of a modified example executes the step S6        and the step S7 simultaneously in the ABS operation control. The        control device 60 of another modified example executes the step        S7 before the step S6 in the ABS operation control.    -   According to the control device 60 of a modified example, the        step S16 to step S18 are omitted from the step shown in FIGS. 3        and 4, in the ABS operation control.    -   According to the control device 60 of a modified example, the        step 19 is omitted from the step shown in FIGS. 3 and 4, in the        ABS operation control. According to this modified example, the        high-performance assist motor 36 which can drive the pump 62 so        as to raise the amount of hydraulic pressure in a short period        of time is preferably used.    -   According to the control device 60 of a modified example, the        state in which the difference between the rotational speed of        the front wheel 14 and the rotational speed of the rear wheel 16        has become greater than or equal to a prescribed speed is        omitted from the prescribed state which is determined in the        step S4, the step S13 and the step S18, shown in FIGS. 3 and 4.    -   The first detection devices 82F and 82R of a modified example        are, instead an angle sensor, a hydraulic pressure sensor for        detecting the hydraulic pressure of the first pipeline 72F and        72R. A hydraulic pressure sensor includes, for example, a        pressure sensor which is provided on the inner wall of the first        pipeline 72F and 72R.    -   The operating device of a modified example includes a grip,        which brakes the rotation of the wheels when rotated around the        axis of the handlebar 18 with respect to the handlebar 18,        instead of the brake levers 20F and 20R. According to this        modified example, the braking force which is applied to the        wheels is adjusted according to the rotation amount of the grip.        The operating device of another modified example includes a        button which is attached to the handlebar 18, instead of the        brake levers 20F and 20R. According to this other modified        example, the braking force which is applied to the wheels is        adjusted according to the amount that the button is pressed.    -   The brake devices 22F and 22R of a modified example is, for        example, a rim brake or a cantilever brake, instead of a disc        brake.    -   The bicycle apparatus 56 of a modified example of the first        embodiment comprises an ABS unit 58R for controlling the braking        force which is applied to the rear wheel 16, instead of the ABS        unit 58F. The ABS unit 58R has substantially the same        configuration as the second ABS unit 58R of the second        embodiment.    -   According to the bicycle apparatus 56 of a modified example of        the first embodiment, the ABS unit 58F is attached to the        outside of the housing 38. As shown in FIG. 6, the bicycle        apparatus 56 further comprises a case 88 which is attached, for        example, to the outside of the housing 38. According to this        modified example, the ABS unit 58F is housed in the internal        space of the case 88. The same modification can be realized in        the second embodiment as well. According to the bicycle        apparatus 56 of a modified example of the second embodiment, for        example, at least one of the first ABS unit 58F and the second        ABS unit 58R is housed in the internal space of the case 88.    -   In the bicycle apparatus 56 of a modified example of the first        embodiment, the pump 62 of the ABS unit 58F is housed in the        internal space of the housing 38, and the other elements of the        ABS unit 58F are disposed outside of the housing 38. According        to this modified example, the other elements of the ABS unit 58F        are, for example, housed in the internal space of a case which        is attached to the outside of the housing 38. The same        modification can be realized in the second embodiment as well.    -   According to the bicycle apparatus 56 of a modified example, the        control of the ABS units 58F and 58R by the control device 60 is        dependent on the operation of the assist selection switch. For        example, the mode is always switched to the ABS operating mode        when the assist ON mode is selected.    -   According to the bicycle 10 of a modified example, the ABS        operation changeover switch is omitted from the operating unit        86. According to this modified example, the mode is switched to        the ABS operating mode by, for example, the assist ON mode being        selected by the assist selection switch. On the other hand, the        mode is switched to the ABS non-operating mode by the assist OFF        mode being selected by the assist selection switch.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. For example, unless specifically stated otherwise,the size, shape, location or orientation of the various components canbe changed as needed and/or desired so long as the changes do notsubstantially affect their intended function. Unless specifically statedotherwise, components that are shown directly connected or contactingeach other can have intermediate structures disposed between them solong as the changes do not substantially affect their intended function.The functions of one element can be performed by two, and vice versaunless specifically stated otherwise. The structures and functions ofone embodiment can be adopted in another embodiment. It is not necessaryfor all advantages to be present in a particular embodiment at the sametime. Every feature which is unique from the prior art, alone or incombination with other features, also should be considered a separatedescription of further inventions by the applicant, including thestructural and/or functional concepts embodied by such feature(s). Thus,the foregoing descriptions of the embodiments according to the presentinvention are provided for illustration only, and not for the purpose oflimiting the invention as defined by the appended claims and theirequivalents.

What is claimed is:
 1. A method of controlling an ABS unit forcontrolling a braking force applied to at least one of a front wheel anda rear wheel of a bicycle, the ABS unit being driven by an assist motorthat is configured to add an assisting force to a manual drive forcethat is inputted from a crankshaft by adding the assisting force to atransmission path having the crankshaft and the at least one of thefront wheel and the rear wheel, the method being operated by a controldevice, the method comprising: determining, by using the control device,whether a vehicle speed of the bicycle is greater than or equal to aprescribed speed; determining, by using the control device, whether thebicycle is in a prescribed state upon determining that the vehicle speedis greater than or equal to the prescribed speed, the prescribed statebeing a state in which a difference between a rotational speed of thefront wheel of the bicycle and a rotational speed of the rear wheel ofthe bicycle is greater than or equal to a prescribed rotational speed:controlling, by using the control device, the ABS unit based on at leastone of the vehicle speed and the prescribed state of the bicycle; andcontrolling the bicycle by driving the assist motor in a firstrotational direction to add assisting force to the manual drive forceinputted from the crankshaft, and driving the ABS unit by driving theassist motor in a second rotational direction that is opposite of thefirst rotational direction.
 2. The method as recited in claim 1, furthercomprising determining whether a front brake lever has been operated. 3.The method as recited in claim 1, further comprising controlling thebraking force applied to the front wheel by controlling a front caliperto the front wheel.
 4. The method as recited in claim 1, wherein theprescribed speed is approximately 5 kilometers per hour.
 5. The methodas recited in claim 3, further comprising controlling the assist motorto control a braking force applied to the front wheel upon determiningthat a front brake lever has been operated and that the vehicle speed ofthe bicycle is greater than or equal to the prescribed speed.
 6. Themethod as recited in claim 5, further comprising controlling a pump thatis driven by the assist motor to supply hydraulic oil to the frontcaliper.
 7. The method as recited in claim 1, further comprisingdetermining whether a rear brake lever has been operated.
 8. The methodas recited in claim 1, further comprising controlling the braking forceapplied to the rear wheel by controlling a rear caliper to the rearwheel.
 9. The method as recited in claim 8, further comprisingcontrolling the assist motor to control a braking force applied to therear wheel upon determining that a rear brake lever has been operatedand that the vehicle speed of the bicycle is greater than or equal tothe prescribed speed.
 10. The method as recited in claim 9, furthercomprising controlling a pump that is driven by the assist motor tosupply hydraulic oil to the rear caliper.
 11. The method as recited inclaim 1, further comprising receiving rotational speed informationdetected by a front wheel detection device and a rear wheel detectiondevice.
 12. The method as recited in claim 1, further comprisingreceiving information regarding an operating state of a brake lever froma brake lever detection device.
 13. The method as recited in claim 12,further comprising controlling the ABS unit in accordance with a firstpattern in which the brake lever is operated to increase hydraulicpressure applied to a brake caliper.
 14. The method as recited in claim13, further comprising controlling the ABS unit in accordance with asecond pattern to reduce hydraulic pressure applied to the brakecaliper.
 15. The method as recited in claim 14, further comprisingcontrolling the ABS unit in accordance with a third pattern to maintainconstant hydraulic pressure applied to the brake caliper.